Interstate battery MTP-H8 is a great replacement

This is my 3rd battery in almost 4 years now .I guess the harsh winter we are having here in WA didnt help matters so this time instead of the Porsche OEM replacement barttery that I chose last time(lasted 18 months) I went with the INTERSTATE MTP-H8 .This battery is somewhat longer then the stock battery and does not require and bracket to be used to keep it in place .Fits real snug and MAN the power it has is really great ! Comes with a 3 year 100% warrenty and a pro rated 84 month warrenty after that .Pretty cool There is a Coupon I printed online for 99.00 !!!! so I am Really happy with the whole deal overall Interstate is a huge sponsor of all kinds of racing and they were rated at the top for quality so Iam recomending them to anyone that has a Battery Issue with their Porsche Cayman . :cheers:

So if I fit really snug in my seat, I don't need to wear a seat belt?

Interesting. So you removed the stock clamp bracket and just sat the battery in the compartment? How about the need for a vent kit adapter, did the dealer provide this? The Interstate website recommends MTP-H8 for our cars but others have had success with the slightly smaller and lighter MTP-91. I'm going to need a new battery myself next year and like to figure all this out now.

Apparently, three different Interstate batteries fit in the Cayman & Boxster : MTP-91 MTP-H8 MTP-H7 I put the H7 in our Boxster on Interstate's advice. I have no idea what the real differences are between these batteries other than a minor size variance. The ratings are different, but the differences are relatively insignificant. When I change the battery on the Cayman I'll probably use the MTP-91, just because it's cheaper.

I thought the end bracket was a required safety feature. I wouldn't drive around without it.

Agree. God forbid you ever get into an accident, you wouldn't want some 60lb + projectile flying around the front trunk! I think pca7ggr is trying to say the same thing in a funny way.

YES it fits snug doesnt need the bracket .I went online for a couple days before I bought it and in some other forums there were guys that did the same .The Battery is almost as long as entire battery stand that it sits on and is slightly wider so it just fits perfect in the tray . we tried moving it around just to make sure and its snug .No seatbelt needed IMO Blueone is correct any of these will work MTP-91 MTP-H8 MTP-H7 but the Firestone shop i went to only had the MTP-H8 looking at the safety aspect maybe I will put a tei down rig for resolve that .Thanks

Yes Pete, that was indeed my point.

Pete: I got the MTP-91. It's the lightest, smallest, and cheapest of those three, but it still has 700 CCA. I've got the same battery in the M3 also. There was a very long battery thread here somewhere. The Interstates come with a vent kit adapter piece to be used with the OEM Moll battery vent tube. The MTP-91 fits perfectly; in order to secure, the fastening nut at the bottom of the tray just needs to be moved over one hole toward the center.

One note about the MTP-H7... it needs to be installed "backwards", because the terminals are in opposite positions compared to the stock Moll unit. Don't mix this up!

Thanks for the info!

Jim Michaels DARN!! man I learn a lot in this forum .I should have gotten the MPT -91 Thanks for all the info guys !! all of you are AWSOME!!!

Re: YES it fits snug